Ball screws are mechanical linear actuators which translate rotational motion into linear motion (and vice-versa). In this regard, standard-type ball screws include a threaded shaft which interfaces with a ball nut via recirculating ball bearings. As well as being able to apply or withstand high thrust loads, they can do so with minimal friction. Ball screws are commonly used in industrial machining operations. In an example implementation, in a machine tool, or robotic assembly, lift action may be accomplished using a ball screw. For example, the ball screw may be oriented vertically and mounted to a lower frame of the tool (or machine or other assembly). A ball nut is mounted to the lifting frame which is the part that ends up moving up and down as the balls crew turns clockwise and counter-clockwise. Because ball screws are capable of spinning so freely (due to their low friction coefficient), if there was no torque on the ball screw to hold it in place, the machine would fall down. Because of this, torque must be applied to the ball screw at all times in order to maintain the position of the machine, for example, by application of torque applied by a motor. Motors employed for this purpose generally include a holding brake for use when power is turned off. This holding brake is a friction type brake. Secondary, redundant brakes may also be employed to hold the machine up when the power is off. These brakes are not used to slow down the machine, but only to hold the machine up when it has already stopped.
While backup friction braking systems may be sufficient in some ball screw applications, the limitations of friction braking systems are widely known in the art, wherein loss of friction will cause the machine to move from its stopped position along the length of the ball screw (in this regard, the ball screw may be back-driven due to its low internal friction due to a loss of friction in the braking mechanism). In order to ensure that a machine supported by a ball screw is positively locked when in a lift position, a novel locking mechanism is desired. In particular, a ball screw locking apparatus is desired wherein the ball screw is physically prevented from turning upon engagement of the locking apparatus.